The NHES used telephone interviews to collect data from the parents of a nationally representative sample of children age 6 and under that had not yet enrolled in kindergarten (Hagedorn, Montaquilla, Carver, O’Donnell, & Chapman, 2005). The 2005 version of the ECPP was the fifth such collection effort and focused on non-parental child care arrangements including care by relatives, care by persons not related to the children, and care in day care centers and programs, including Head Start and pre-kindergarten programs. Since 6 year old preschoolers are uncommon (NHES, 2005), they are not included in this particular analysis. After these adjustments, records from 7,198 children were examined (6,066 urban and 1,132 rural).
The public-use version of the NHES contains flags to identify the urban and rural status of the children in the sample, as defined by the urban and rural makeup of the zip codes in which they reside. This methodology is based on classifications used by the Census Bureau; zip codes are considered urban if they are located within urban areas (UA) or clusters (UC), and zip codes that are not defined as urban under this definition are classified as rural. When zip codes contain both urban and rural areas within their borders, the urban/rural classification is determined by the larger of the two populations (Hagedorn, et al., 2005). Hence, zip codes that have more rural residents than urban residents are considered rural, and zip codes containing more urban residents than rural residents are considered urban.
Since zip codes are much smaller than counties, this classification system is able to classify neighborhoods as being urban or rural status more accurately than many other categorization systems. However, this sorting system differs from many county-based systems, including the metropolitan/non-metropolitan system used by the Office of Management and Budget (OMB), in that it does not consider employment commuting patterns for its classifications. The end result is that the NHES classifies as rural some children living in sparsely populated counties relatively near urban centers that would be classified as urban or metropolitan in other data sets. It is also important to note that the urban/rural classification is based on the zip code in which the children reside, which may differ from the urban/rural status of the zip code in which the care is provided.
 Only 413 records for 5 year old children were in the sample because children of this age are often in kindergarten and thus excluded from the NHES, ECPP.